Biology

Kakuna is a yellow, cocoon Pokémon. Kakuna has a dome-shaped head and black, triangular eyes. It has two scythe-like arms in the middle of its body. When it comes close to evolving, its body gives off heat that makes it warm to the touch. Kakuna remains virtually immobile and waits for evolution often hanging from tree branches by long strands of silk. When attacked, however, it can extend its poison barbs. Kakuna nests in forests and misty wooded areas. Occasionally, it will also nest at the mouths of tunnels and caves as seen in Pokémon Snap.

Kakuna remains virtually immobile as it clings to a tree. However, on the inside, it is extremely busy as it prepares for its coming evolution. This is evident from how hot the shell becomes to the touch.

Trivia

Kakuna is tied with them as the weakest evolved Pokémon in the games, by average base stats.

In the Pokémon Red and Blue beta, "Kokoon" was the prototype English name for Kakuna. This is the same as its romanized Japanese name.

The "arms" on Kakuna seen in its Red and Blue sprite are commonly mistaken to be a sprite error, as they are rarely shown in any other media. They have so far only been shown on its Red and Blue sprite and a Pocket Monsters Bandai card.

In the anime, Kakuna has been shown evolving more than any other Pokémon.

Origin

Its design appears to be based on a chrysalis or the pupa stage of a bee (more specifically the common honeybee pupa.)